U.S. Department of Energy - Energy Efficiency and Renewable Energy

Wind Program

Spirit Lake School District Case Study

July 31, 2012

The Spirit Lake School District in Iowa installed a 250-kilowatt (kW) wind turbine in 1993 and a 750-kW turbine in 2001, providing an example of installed renewable energy for other schools across the nation to follow while offsetting approximately 46% of the district's electricity needs. The following case study summarizes the project's history, including cost, funding, and technical details.

250-kW Turbine

Spirit Lake School District paid $239,500 for its first turbine in 1993, which powers the elementary school. The district received a grant of $119,000 from the U.S. Energy Department and covered the remaining project cost via a low-interest loan from the Energy Council of the Iowa Department of Natural Resources.

The district made the final loan payment in 1998, 3.5 years ahead of schedule.

The Windworld turbine is 140 feet tall and has a 90-foot blade diameter.

750-kW Turbine

The district installed a second wind turbine in 2001 for a total cost of $780,000. The Iowa Energy Center's Alternative Energy Revolving Loan Program provided a $250,000 loan with no-interest financing. Spirit Lake also received a $580,000 loan from the Iowa Department of Natural Resources with a 5.1% interest rate.

The NEG Micon averaged nearly 83% of projected output in its first 5 years. The turbine's $120,000 in annual production exceeded the district's yearly loan payment amount of $93,000.

The district initially used the surplus revenue to pay down its 10-year loans but is now paying for other district expenses instead.

The 750-kW NEG Micon turbine is 180 feet tall with a blade diameter of 160 feet.

The district paid an annual fee of $5,000 for a service agreement with NEG Micon to cover all parts, labor, and scheduled maintenance expenses for the first 5 years of the project.

The turbines have required only two major repairs. First, the computers had to be replaced in 2003 following a lightning strike. School insurance covered all but $1,000 of the $4,400 expense. Second, the NEG Micon gearbox had to be replaced, but a warranty agreement covered the entire fee, which exceeded $50,000.